测量了含HFC134a和CFC12的光滑管和微翅片管的蒸发和冷凝传热系数。微翅片管是一种内部增强型管，其特点是许多小翅片沿着管螺旋向下。例如，在本研究中，微翅片管有60个翅片，高度为0.2mm，螺旋角为17度。传热测量是在内径为8.0mm（0.31英寸）的3.67米（12英尺）长的管子上进行的。蒸发试验条件为5℃-15℃，冷凝试验条件为30℃-50℃。制冷剂质量流量的变化范围为130 kg/m2。 s（95860磅/英尺2.h）至400千克/平方米。s（294000磅/英尺2.h）。当将HFC134a与CFC12在光滑管中的质量流量相似时，蒸发和冷凝传热系数分别高出约40%和25%。传热系数的一个更相关的比较是在相同的冷却（或加热）能力下。在这种情况下，HFC134a的传热系数比CFC12的蒸发和冷凝值高出约10%。与光滑管相比，微翅片管在所有条件下都能产生更高的传热系数和压降。 例如，对于HFC134a，传热强化系数（定义为微翅片管的对流传热系数除以在类似条件下测得的光滑管的值）不同。蒸发过程中和蒸发过程中的5到2.5。冷凝过程中为8至2.5。两种制冷剂的压降惩罚因子（定义类似于强化因子）通常小于传热强化因子。然而，对于最低温度和最高质量流量下的HFC134a，惩罚因子略高于增强因子。 关键词:蒸发、冷凝、R134a、R12、制冷剂、压降、传热系数、蒸发器、管、翅片管、比较、测量、热流引用:ASHRAE学报，第97卷，第页。1991年，印第安纳波利斯

Evaporation and condensation heat transfer coefficients were measured for smooth and micro-fin tubes with HFC134a and CFC12. Micro-fin tubes are internally enhanced tubes that are characterised by numerous small fins that spiral down the tube. For example, in this study, the micro-fin tube had 60 fins with a height of 0.2mm and a 17 deg spiral angle. Heat transfer measurements were performed on 3.67m (12 ft) long tubes with inside diameters of 8.0mm (0.31 in.). Test conditions varied from 5 deg C to 15 deg C for evaporation and 30 deg C to 50 deg C for condensation. The refrigerant mass flux was varied from 130 kg/m2.s (95,860 lb/ft2.h) to 400 kg/m2.s (294,000 lb/ft2.h). When HFC134a was compared to CFC12 at similar mass fluxes in smooth tubes, the evaporation and condensation heat transfer coefficients were about 40% and 25% higher, respectively. A more relevant comparison of heat transfer coefficients is at equivalent cooling (or heating) capacities. In this case, the HFC134a heat transfer coefficients were about 10% higher than CFC12 values for both evaporation and condensation. The micro-fin tube produced higher heat transfer coefficients and pressure drops for all conditions when compared to the smooth tube. For example, for HFC134a, heat transfer enhancement factors (defined as the convective heat transfer coefficients for the micro-fin tube divided by the value for the smooth tube measured at similar conditions) varied from.5 to 2.5 during evaporation and from.8 to 2.5 during condensation. Pressure drop penalty factors (defined similarly to enhancement factors) for both refrigerants were usually less than the heat transfer enhancement factors. However, in the case of HFC134a at the lowest temperature and highest mass flux, the penalty factor slightly exceeded the enhancement factor.KEYWORDS: evaporation, condensation, R134a, R12, refrigerants, pressure drop, heat transfer coefficient, evaporators, tubes, finned tubes, comparing, measuring, heat flow